US6595684B1ExpiredUtility

System and method for evaluating a structure

Assignee: NORTHROP GRUMMAN CORPPriority: Nov 3, 1999Filed: Nov 3, 1999Granted: Jul 22, 2003
Est. expiryNov 3, 2019(expired)· nominal 20-yr term from priority
G01N 25/72
86
PatentIndex Score
102
Cited by
17
References
22
Claims

Abstract

In a system ( 10 ) for evaluating a structure ( 20 ), the structure ( 20 ) has a predetermined baseline thermal signature. The system ( 10 ) includes a thermal source ( 30 ) located at least partially inside the structure ( 20 ). The thermal source ( 30 ) is operable to generate a predetermined amount of heat, which heats the structure ( 20 ). The system ( 10 ) also includes a detection device ( 40 ) that is operable to determine the temperature at various points of the structure ( 20 ). The system ( 10 ) further includes a computer ( 50 ) that is coupled to the detection device ( 40 ). The computer ( 50 ) is operable to generate a thermal signature of the structure ( 20 ) based on the temperature at the various points. The generated thermal signature of the structure ( 20 ) is compared to the baseline thermal signature of the structure ( 20 ) to determine whether anomalies exist in the structure ( 20 ).

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
       1. A system for evaluating a structure, the system comprising: 
       a) a structure to be evaluated, the structure having a predetermined baseline thermal signature and formed from a web of interwoven fibers including at least one electrically conductive fiber;  
       b) a thermal source comprising a power-supply and the at least one electrically conductive fiber, the power supply operable to supply power to the at least one electrically conductive fiber to heat the structure;  
       c) a detection device operable to detect a thermal energy at various points of the structure; and  
       d) a computer coupled to the detection device, the computer operable to generate a thermal signature of the structure based on the thermal energy at the various points; and  
       e) wherein the generated thermal signature of the structure is compared to the baseline thermal signature of the structure to determine whether anomalies exist in the structure.  
     
     
       2. The system of  claim 1 , wherein the computer is coupled to the power supply and is operable to direct the power supply to produce a steady-state current in the electrically conductive fiber. 
     
     
       3. The system of  claim 1 , wherein the web of interwoven fibers are coupled to one another with a resin. 
     
     
       4. The system of  claim 3 , wherein the electrically conductive fiber comprises graphite. 
     
     
       5. The system of  claim 1 , wherein the electrically conductive fiber is laminated to an interior surface of the structure. 
     
     
       6. The system of  claim 1 , wherein the electrically conductive fiber has a nonhomogeneous resistance, the nonhomogeneous resistance causing the heat output of the electrically conductive fiber to vary between different locations of the structure. 
     
     
       7. The system of  claim 1 , wherein the detection device comprises an infrared detection device located outside the structure, the infrared detection device capable of detecting infrared radiation emitted from the structure. 
     
     
       8. The system of  claim 1 , wherein the detection device comprises a thermocouple located inside the structure. 
     
     
       9. The system of  claim 1 , wherein the baseline thermal signature is representative of a non-defective structure. 
     
     
       10. The system of  claim 1 , wherein the computer is further operable to compare the generated thermal signature with the baseline thermal signature. 
     
     
       11. The system of  claim 10 , wherein the computer is further operable to determine if an anomaly exists in the structure. 
     
     
       12. The system of  claim 1 , wherein the computer is coupled to the power supply and is operable to direct the power supply to generate a predetermined amount of power to the at least one electrically conductive fiber. 
     
     
       13. The system of  claim 1 , wherein the at least one electrically conductive fiber is interwoven in a continual looping manner. 
     
     
       14. The system of  claim 1 , wherein the computer is coupled to the power supply and is -operable to direct the power supply to produce a single pulse current in the electrically conductive fiber. 
     
     
       15. A method for evaluating a structure, the method comprising: 
       determining an amount of heat to be transferred to the structure;  
       generating the amount of heat within the structure by directing, by a computer, a power source to deliver a corresponding amount of power to an electrically conductive fiber located at least partially inside the structure;  
       detecting the thermal energy at various points of the structure;  
       generating a thermal signature of the structure based on the thermal energy at the various points; and  
       comparing the generated thermal signature of the structure to a predetermined baseline thermal signature of the structure.  
     
     
       16. The method of  claim 15 , wherein the electrically conductive fiber comprises graphite and is embedded in the structure. 
     
     
       17. The method of  claim 15 , wherein detecting the thermal energy at various points of the structure is performed by an infrared detection device located outside the structure, the infrared detection device capable of detecting infrared radiation emitted from the structure. 
     
     
       18. The method of  claim 15 , wherein detecting the thermal energy at various points of the structure is performed by thermocouples located inside the structure. 
     
     
       19. The method of  claim 15 , wherein the baseline thermal signature is representative of a non-defective structure. 
     
     
       20. The method of  claim 15 , further comprising determining whether anomalies exist in the structure. 
     
     
       21. The method of  claim 15 , further comprising: 
       varying the amount of heat within the structure over time; and  
       generating the thermal signature of the structure that varies with time.  
     
     
       22. A system for evaluating a structure, the system comprising: 
       a structure to be evaluated, the structure formed from a web of interwoven fibers coupled together by a resin;  
       at least one electrically conductive fiber associated with the web of interwoven fibers;  
       a power supply coupled to the at least one electrically conductive fiber, the power supply operable to supply power to the at least one electrically conductive fiber to heat the structure;  
       a detection device operable to detect a thermal energy at various points of the structure; and  
       a computer coupled to the detection device, the computer operable to generate a thermal signature of the structure based on the thermal energy at the various points.

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